The present invention relates to a sump pump comprising a centrifugal pump located at the bottom of a sump in which water is collected to be discharged when the water reaches a predetermined level.
The pump has the axis of its rotor vertical and includes a housing having a water inlet at its bottom. The motor is connected directly to the pump rotor and includes a casing the bottom wall of which is spaced above the top wall of the pump housing and is provided with air inlet ports. The motor casing has top air outlet ports extending around its circumference adjacent the top. The motor is provided with a conventional fan within the casing. The motor casing is located centrally in a chamber having a closed cylindrical side wall spaced uniformly a slight distance from the motor casing, and defines a 360.degree. restricted air passage which extends for the full axial length of the motor casing. The top wall of the chamber is sealed to the lateral wall and serves as a mount for a switch which controls the motor. The bottom wall of the chamber is formed by the top wall of the pump housing.
Accordingly, the motor is cooled by air entrapped within the chamber, and the air is cooled by contact with the lateral wall of the chamber, which in turn is cooled by water in the sump to the level of the water. In addition, the entrapped air is cooled by flowing over the top wall of the pump housing, which of course is cooled by the sump water passing through the pump is in operation.
An important factor in the cooling of the circulating air is that an elongated annular passage of restricted uniform width is provided so that circulating air is positively cooled during its flow out of the upper motor casing outlet ports, down through the elongated, restricted annular passage and thence radially inwardly across the 360.degree. space surrounding the mounting connection between the pump and motor.
It will be observed that the motor is fully sealed against entrance of water into the totally enclosed submersible chamber in which the motor casing is received.
This construction permits use of a motor normally intended for cooling by ambient air to be located in a sealed chamber which is submersible while entrapped air flow is directed for efficient cooling. This opens a broader field for a regular sump pump motor intended to be cooled by flow of room air, and eliminates the need for cooling oil inside the housing. In addition the unique design makes it simple to increase the height of the chamber, thus increasing the volume of air entrapped in therein, and also increasing the off and on limits of the liquid level. It has all of the advantages and none of the disadvantages of an upright sump pump. It makes it possible to use any standard sump pump motor in the 48 frame, which is standard as manufactured by General Electric, Westinghouse, Emerson, Century and many other motor manufacturers.
The combination disclosed herein completely overcomes the disadvantage of prior "upright" sump pumps, in which, if they fail to operate, due to mechanical trouble or power failure, permit the water to rise over the switch and motor and make the pump inoperable.
My construction may be described as an upright-submersible float operated motor driven sump pump. This is accomplished by mounting the motor on a hollow boss on the exact center, so that the motor is mounted on this boss, with its shaft extending through it for connection to the pump impeller, the boss constituting the sole mounting of the motor on the pump .